"So just how much horsepower do you need to win?" I ask McCulloch. He grins. "More."
No one knows exactly how much power these engines produce on nitro. Starting with a custom-built, hugely strengthened aluminum block based on the classic 426 Chrysler Hemi, they are so explosively powerful that putting one on a dynamometer to measure output is unthinkable. The same bored-out 500-cubic-inch engine, running on more benign alcohol, has been dyno'ed, and extrapolations made for nitro. For years, the figure quoted was 6,000 horsepower, but today there is more and more talk of 7,000.
With this much power, keeping the car from flying is serious business. At 300-plus mph, faster than most private planes, a Top Fuel car's carbon fiber rear wing produces something north of 6,000 pounds of downforce. The front wing brings another 1,800 pounds to the party. The car would pop the mother of all wheelies-a "blow-over"-were it not for the rather dainty-looking wheelie-bar out back.
Legend has it that a hot-rod magazine in the 1950s published a scientist's article proving that it was physically impossible for a car to accelerate to 150 mph in the quarter mile. The introduction of nitromethane and vastly improved drag tires in the early 1960s opened a new world of speed and thunder. Unlike gasoline, oxygen is built right into nitro-CH3NO2. Gasoline's C8H18 formula requires a lot of added O to ignite. Nitro actually contains less energy per ounce than gas, but requires only about an eighth as much added air, so a much higher fuel-to-air ratio is possible in the cylinders. By volume, a nitro engine is more than twice as powerful as a gas engine.
Touchy stuff, though, nitro. The strongest engines can explode, and that's most unpleasant if you're sitting behind one. Engine and transmission were in front of the driver until the early 1970s, when the transmission in driver Don "Big Daddy" Garlits' Swamp Rat XIII dragster exploded, cutting the car in two and severing part of his foot. Swamp Rat XIV was the first successful rear-engined rail.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.